@Test
public void handleModelReturnValue() throws Exception {
mavContainer.addAttribute("attr1", "value1");
Model returnValue = new ExtendedModelMap();
returnValue.addAttribute("attr2", "value2");
processor.handleReturnValue(returnValue , returnParamModel, mavContainer, webRequest);
assertEquals("value1", mavContainer.getModel().get("attr1"));
assertEquals("value2", mavContainer.getModel().get("attr2"));